Methods for forming composite articles from non-crimp fabrics

Abstract

Methods for forming composite articles include providing a non-crimp fabric (NCF) comprising a plurality of fiber plies maintained in a layup by stitching, wherein the stitching exhibits a lower structural tolerance to heat and/or UV light relative to the fiber plies, selectively degrading the stitching in one or more areas using heat or UV light, draping the NCF on a contoured article, applying a polymer matrix material to the draped NCF, and curing the polymer matrix material to form a contoured composite article. The stitching can be degraded in regions of the NCF which, when draped on the contoured article, correspond to topological features of the contoured article. Degrading the stitching can comprise breaking the stitching. The fiber plies can comprise carbon fibers, glass fibers, and/or basalt fibers. The contoured article can be tooling and/or an automotive component. The NCF can be a bi-axial NCF.

The invention claimed is: 
     
       1. A method for forming a composite article, the method comprising:
 providing a non-crimp fabric (NCF) comprising a plurality of fiber plies maintained in a layup by stitching, wherein the stitching exhibits a lower structural tolerance to heat and/or UV light relative to the fiber plies; 
 selectively reducing a thread strength or elasticity of the stitching in one or more predefined areas of the NCF using heat or UV light; 
 breaking the stitching with the reduced strength or elasticity in only the one or more predefined areas while leaving substantially intact the stitching in remaining regions of the NCF; 
 draping, subsequent to breaking the stitching, the NCF on a contoured article wherein, as a result of selectively breaking the stitching in the one or more predefined areas using heat or UV light, the NCF corresponds to topological features of the contoured article; 
 applying, subsequent to draping the NCF, a polymer matrix material to the draped NCF; and 
 curing the polymer matrix material to form a contoured composite article. 
 
     
     
       2. The method of  claim 1 , wherein the one or more predetermined areas of the NCF with the broken stitching, when the NCF is draped on the contoured article, align with the topological features of the contoured article. 
     
     
       3. The method of  claim 2 , wherein the topological features of the contoured article aligned with the broken stitches exhibit variation in more than one dimension. 
     
     
       4. The method of  claim 1 , wherein the fiber plies comprise carbon fibers, glass fibers, basalt fibers, or any combination thereof. 
     
     
       5. The method of  claim 1 , wherein the contoured article comprises tooling. 
     
     
       6. The method of  claim 1 , wherein the contoured article comprises an automotive component. 
     
     
       7. The method of  claim 1 , wherein the NCF comprises a bi-axial NCF. 
     
     
       8. A method for forming a composite article, the method comprising:
 providing a non-crimp fabric (NCF) comprising a plurality of fiber plies maintained in a layup by stitching, wherein the stitching exhibits a lower structural tolerance to heat relative to the fiber plies; 
 selectively reducing a thread strength or elasticity of the stitching in one or more predefined areas of the NCF using heat; 
 breaking the stitching with the reduced strength or elasticity in only the one or more predefined areas while leaving substantially intact the stitching in remaining regions of the NCF; 
 draping, subsequent to breaking the stitching, the NCF on a contoured article wherein, as a result of selectively breaking the stitching in the one or more predefined areas using heat, the NCF corresponds to topological features of the contoured article; and 
 subsequently: 
 applying a polymer matrix material to the draped NCF; and 
 curing the polymer matrix material to form a contoured composite article. 
 
     
     
       9. The method of  claim 8 , wherein the fiber plies comprise carbon fibers, glass fibers, basalt fibers, or any combination thereof. 
     
     
       10. The method of  claim 8 , wherein the stitching comprises one or more polyamides, one or more polyesters, polyurethane, one or more rayon materials, polypropylene, one or more polyglycolic acids, one or more polyvinyl alcohols, or any combination thereof. 
     
     
       11. The method of  claim 8 , wherein the stitching is selectively broken by contacting the NCF with a heated contoured roller or a heated contoured stamp. 
     
     
       12. The method of  claim 11 , wherein the contoured roller or contoured stamp comprises contoured portions which are heated to at least a melting point of the stitching. 
     
     
       13. The method of  claim 8 , wherein the stitching is selectively broken by a laser, a rastered induction heating tool, or open-air plasma. 
     
     
       14. A method for forming a composite article, the method comprising:
 providing a non-crimp fabric (NCF) comprising a plurality of fiber plies maintained in a layup by stitching, wherein the stitching exhibits a lower structural tolerance to UV light relative to the fiber plies; 
 selectively reducing a thread strength or elasticity of the stitching in one or more predefined areas of the NCF using heat; 
 breaking the stitching with the reduced strength or elasticity in only the one or more predefined areas while leaving substantially intact the stitching in remaining regions of the NCF; using UV light; 
 draping, subsequent to breaking the stitching, the NCF on a contoured article wherein, as a result of selectively breaking the stitching in the one or more predefined areas using UV light, the NCF corresponds to topological features of the contoured article; and 
 subsequently: 
 applying a polymer matrix material to the draped NCF; and 
 curing the polymer matrix material to form a contoured composite article. 
 
     
     
       15. The method of  claim 14 , wherein the stitching is selectively broken using UV light by applying a mask to the NCF, wherein the mask comprises one or more apertures which correspond to regions of the NCF in which stitching breaking is desired, and exposing the mask to UV light. 
     
     
       16. The method of  claim 14 , wherein the stitching is selectively broken by a shrouded UV light source. 
     
     
       17. The method of  claim 14 , wherein the fiber plies comprise carbon fibers, glass fibers, basalt fibers, or any combination thereof. 
     
     
       18. The method of  claim 14 , wherein the stitching comprises one or more polyamides, one or more polyesters, polyurethane, one or more rayon materials, polypropylene, one or more polyglycolic acids, one or more polyvinyl alcohols, or any combination thereof. 
     
     
       19. The method of  claim 1 , wherein the stitching is applied in a hybrid chain/tricot pattern. 
     
     
       20. The method of  claim 1 , wherein the stitching is formed from a polymeric material containing a filler, the filler including a plurality of metallic particles with an average diameter of about 10 nm to about 20 μm or a UV light additive configured to absorb UV light and degrade to generate organic free radicals.